Technology Case Studies 3

Largest HEP dam in the world - 23,000 mW

Based on the Yangtze river

Constructed between 1994 and 2011

Thought to cost $25 billion but actually cost close to $100 billion

Power from 26 turbines

Funded by the China Development Banks, as well as companies and banks in France, Canada, Brazil, Germany and Switzerland

Positive environmental consequences: HEP produces no GHGs, dam replaces 50 million tonnes of coal in China's energy use, acid rain prevented, drought relief for areas downstream.

A main aim of the dam is flood control

Negative environmental consequences: Landslides and bank collapses threaten water quality, species such as the Chinese river dolphin have become threatened, pollution occurs as the river can't 'flush' itself, earthquakes are more common.

Positive social consequences:HEP can be used as an energy supply for many homes and businesses, health standards improve as air quality improves, new jobs created, death by flooding reduced.

Negative social consequences:13 cities, 140 towns and 1,350 villages submerged as of 2010, 4 million displaced, loss of historical sites, many have lost their livelihoods from flooding of farmland.

Investment of $62 billion by the Chinese government to divert more than 45 billion cubic metres of water from the Yangtze River in the south to the Yellow River basin in the arid north. 

Northern China has the most populous megacities, which have the greatest demands for water in order to continue their development.

The project is dependent on loans despite some central and local government funding already.

Positive environmental consequences:Domestic waste water will be recycled for agricultural use, soil erosion and land desertification will decrease in the north, water quality will greatly improve.

Negative environmental consequences:The promotion of industrial development will lead to increased pollution, biodiversity could reduce with the lowering levels of the Yangtze river, the Han river will lose its ability to 'flush' itself which causes pollution.

Positive social consequences:180,00 jobs will be created with phase 1 of the project, economic growth will occur in surrounding areas, farmers will benefit from the promotion of local rural economic development.

Negative social consequences:330,000 people have already been relocated, many farmers have been forced to give up their land, demand already outstrips supply and environmental groups say this should be lowered before the project goes ahead.

Designed to store rainwater for recycled use, such as irrigation.

Developed as part of a World Bank sponsored water and sanitation programme between 1995 and 1998.

Implemented by Practical Action, an NGO

Implemented

Tanks are designed for individual households or for group household use.

Positive environmental consequences:Soil erosion is limited with tanks as opposed to dug holes to keep underground supplies.

Positive social consequences:Food security increases as crops can be irrigated and animals can be watered, water is also used for daily needs like cooking and washing, a first flush mechanism diverts the dirty first water.

Negative social consequences:Supplies can dry up in the dry season meaning families need to find alternative sources, families often have to pay for guttering which can't always be afforded.

Sulphur aerosols

Space mirrors

Ocean fertilisation

Synthetic trees

Similarly to global dimming from a volcanic eruption, sulphur particles are scattered in the stratosphere by balloons or planes to block incoming solar radiation, cooling the planet.

Problems:Replenishment is needed which will cost $50billion every 2 years, sulphur could damage the ozone layer, acid rain is caused and rainfall patterns will be disrupted.

Launching giant mirrors into orbit to reflect solar radiation away from the Earth, creating a cooling effect.

Problems:An attempt was done in 1999 but failed, the technology for large lightweight mirrors hasn't been developed yet, costs could exceed $1 trillion and warmer high latitudes and cooler tropics would be created, causing ecosystem shifts.

Adding iron particles to the ocean to encourage plankton, which sequesters the carbon dioxide. When plankton dies, it sinks to the sea floor.

Problems:Trials have been abandoned after a year, 6 billion tonnes of carbon dioxide needs to be sequestered per year at $5 per tonne, oceans could become acidified as a result of adding iron, which can harm biodiversity.

'Trees' designed by Klaus Lackner are intended to sequester 90,000 tonnes of carbon dioxide per year. The 'trees' would use sodium hydroxide to capture carbon directly.

Problems:Carbon once captured needs to be buried in deep sites, hundreds of thousand of trees are needed taking up large amounts of space, costs are around $30 per tonne of carbon dioxide, trees need to be powered.

Organic

Manufactured chemicals, plant growth hormones, antibiotics and GM organisms are excluded

International Federation of Organic Agriculture Movements (IFOAM)

Soil fertility increased with crop rotation

Labour intensive

More expensive than regular yields

Hydroponics

Growing crops using mineral nutrient solutions in water, without the use of soil

No reliance on energy from the sun

Water is conserved as the nutrient/water mix is often recycled

Tastes of foods can be altered by using different nutrient mixes

Increased risk of immediate plant death due to no buffer from soil

Three Gorges Dam

South-North Water Transfer

Sri Lankan Pumpkin Tank

Geo-engineering

Farming Technologies